Process for the dyeing of mixtures of cellulose and polyester fibers

ABSTRACT

Process for the dyeing of mixtures of cellulose fibers and fibrous materials of linear polyesters in a single bath with reactive dyestuffs and dispersion dyestuffs by treating the said fibrous materials at temperatures in the range of about 20* to 80* C. with dyebaths which contain alkaline agents in addition to the said dyestuffs, then adjusting the pH of the bath to a value in the range of 3.5 to 6 by adding free acids, and completing the dyeing at temperatures in the range of from about 95* C. to 140* C.

llnited States Patet lnventor Wolfgang Schulz Pfullingen, Germany Appl. No. 708,510 Filed Feb. 27, 1968 Patented Nov. 2, 1971 Assignee Farhwerke Hoechst Aktiengesellschaft vormals Meister Lucius 8: Bruning Frankfurt am Main, Germany Priority Mar. 3, 1967 Germany F 5 1703 PROCESS FOR THE DYEING OF MIXTURES OF CELLULOSE AND POLYESTER FIBERS 5 Claims, No Drawings 11.8. C1 8/2] C, 8/14, 8/54.2, 8/179, 8/163 Int. Cl D06p 3/82 Field of Search 8/14, 54.2, 179

References Cited UNITED STATES PATENTS 5/1965 Cole et a1 8/21 3,288,551 11/1966 Raff 8/21 3,413,074 11/1968 Lowande etal. 8/21 OTHER REFERENCES Du Pont (1), Technical lnformation, Bulletin D-73, Feb. 1956,pages l5 and 16 8-179 American Dyestuff Reporter, Feb. 8, 1960, pages 5 2(P83)- 54(P85) 8-21 Du Pont (2), Technical Information, Bulletin D-l92, July 1966, page 9 8-179 Primary Examiner-George F. Lesmes Assistan! Examiner-H. Wolham Arrome \'Curtis, Morris and Safford PROCESS FOR THE DYEING OF MIXTURES OF CELLULOSE AND POLYESTER FIBERS It is known that the dyeing of textile materials consisting of mixtures of cellulose fibers and fibers of linear polyesters with reactive and dispersion dyestuffs in a single bath is connected with difficulties. The difficulties are due to the different dyeing conditions of these two different dyestuff classes. Thus, dispersion dyestuffs usually require long dyeing periods and dyeing temperatures of above 95 C. In dyeing, the dispersion dyestuffs are applied as far as possible in an acid medium, because the dyestuff dispersions have partly a low stability in the alkaline range and, additionally, at such high temperatures the action of the alkalis causes some of the dyestuffs to undergo chemical modifications which entail changes of the shade and loss of color yield as well as impairment of the fastness properties of the dyeings. Reactive dyestuffs, on the other hand, require alkaline conditions in order to render possible the reaction with the hydroxyl groups of cellulose. A prolonged dyeing period, however, especially at temperatures of more than 95 C, entails splitting of the dyestuff-fiber linkage which thus reduces the color yield on the goods.

Now, we have found that these disadvantages can be avoided and that mixtures of cellulose fibers and fibrous materials of linear polyesters can be dyed in a single bath with reactive dyestuffs and dispersion dyestuffs by treating these materials at temperatures in the range of from about 20 to 80 C. with a bath which contains, in addition to the aforesaid dyestuffs, alkaline agents, then adjusting the pH of the bath to a value in the range of from 3.5 to 6 by the addition of a free acid and, finally, completing the dyeing at temperatures in the range of from about 95 to 140 C.

The process of the present invention permits adjusting the pHvalue of the dyebath in such a manner that it corresponds to the respective fixing conditions of the reactive dyestuffs and dispersion dyestuffs, thus making the use of separate baths unnecessary. it is very surprising that hydrolysis of the linkage between the reactive dyestuff and the fiber does not take place at these high temperatures in the acid medium and that thus no loss of color yield occurs.

In the process of the present invention, the textile materials are treated with a bath which is kept at temperatures of about 20 to 80 C, preferably about 40 to 60 C, and which contains the dissolved reactive dyestuff, the dispersion dyestuff and the alkaline agents, for a period of time of 10 to 60 minutes, preferably to minutes; during this time the reactive dyestuff is fixed on the cellulose fiber. Then, free acid is added to the dyebath until it shows a pl-l-value in the range of from 3.5 to 6.0, preferably 4.5 to 5.5. The dyebath is then heated to about 95 to 140 C. and kept for about 30 minutes to 3 hours, preferably 45 to 90 minutes, at this temperature. During this time, the dispersion dyestuff is fixed on the polyester fiber. If the fixation of the dispersion dye-stuff is effected at a temperature of about 95 to 110 C. it is of advantage to add a so-called carrier, either after the acidification or at the same time as the acid, to the dyebath. It is also possible to add the carrier already to the alkaline bath. After dyeing, the goods are rinsed and soaped and finished in the usual manner.

The process of the present invention for the dyeing of mixtures of cellulose fibers and fibrous materials of linear polyesters in a single bath has the advantage over the hitherto .used two-bath process that by it the dyeing time is reduced by about 25 to percent. When program controlled dyeing apparatuses are used it also offers another advantage: after the charging of the dyeing apparatus and filling of the required acid into the additional container connected with the dyeing apparatus, the dyeing program can proceed automatically, without operator, when using the process of the present invention. In the conventional two-bath process, the dyeing apparatus has to be charged twice.

As reactive dyestuffs, there may be used in the process of the present invention organic dyestuffs which contain, as the reactive moiety, at least one vinylsulfone group or at least one group which during dyeing forms a vinylsulfone group by the action of the alkaline agerfts. As basic dyestuffs, those of the anthraquinone, azo and phthalocyanine series may be used; the azo and phthalocyanine dyestuffs may be metal-free or metallized. Among the class of groupings which are converted by the alkaline treatment into a vinylsulfone group capable of reacting with the cellulose fiber, there may be mentioned, as examples, especially the sulfuric acid esters and the thiosulfuric acid esters of B-hydroxyethylsulfone groups.

As dispersion dyestuffs, there may be used the dyestuffs well known for the dyeing of fibrous materials of linear polyesters, for example those of the series of azo or anthraquinone dyestuffs.

The alkaline agents to be added to the dyebaths according to the process of the present invention may be applied in the quantities commonly used in the dyeing with reactivedyestuffs. The baths should contain the alkaline agents in such a quantity that their pH is adjusted to a value in the range of from 9 to 12 and maintained during fixation of the reactive dyestuffs. As alkaline agents, there may be used inorganic compounds having an alkaline action, for example sodium carbonate, sodium bicarbonate, trisodium phosphate, disodium phosphate, sodium hydroxide, sodium silicates, the corresponding potassium compounds or mixtures of these alkaline agents, preferably mixtures of sodium hydroxide solution and sodium carbonate.

As the free acid which is used according to the present invention for adjusting acid fixing conditions required for the application of the dispersion dyestuffs, there may be used an inorganic acid such as hydrochloric acid, sulfuric acid or phosphoric acid, or an organic acid such, for example, as acetic acid or formic acid. Mixtures of these acids may also be used. Acetic acid is preferably used. The quantity of the free acid to be added to the dye baths after fixation of the reactive dyestuffs depends in the first instance on the alkali content of the bath and therewith indirectly on the quantity of reactive dyestuffs used, which again depends on the mixing ratio of the portions of cellulose and polyester fibers in the textile materi' als to be dyed.

As carriers which may, if desired or required, be used simultaneously, there may be mentioned the auxiliary agents known in the dyeing of polyester fibers, for example. o-phenylphenol, p-phenyl-phenol, benzoic acid alkyl esters and salicylic acid alkyl esters.

The dyebaths may furthermore contain the usual adjuvants, for example electrolytes, wetting or dispersing agents.

The textile materials to be dyed according to the process of the present invention which consist of mixtures of native or regenerated cellulose fibers and fibrous materials of linear polyesters, preferably polyethylene glycol terephthalate. may be present in the various forms ofmanufacturing, for example the form offlocks, bands, yarns, tissues or knit tissues.

The following examples illustrate the invention but they are not intended to limit it thereto:

EXAMPLE l A mixture of polyester fibers and staple fibers, in a mixing ratio of 70:30, in the form of a yarn wound on taper bobbins, was dyed at a goods-to-liquor ratio of H5, for 30 minutes in a high-temperature dyeing apparatus at 60 C. with a bath containing, per litre of water, the following dyestuffs in commercial form and constitution:

NOI

CN A red dyeing was obtained in which the polyester and staple l fiber portions of the mixed yarn were well dyed tone-in-tone. 0, 26g. o,N--N=N- CH,CH,OCOCH; 5 EXAMPLE 3 A fabric made of a mixture of mercerized cotton fibers and CH;CH -0-C 0-011 polyester fibers in a mixing ratio of 67:33 was dyed at a goodsto-liquor ratio of 1:15 for 30 minutes at 60 C. in a high-tem- R perature beam dyeing apparatus with a bath containing. per 10 liter of water, the following dyestuffs in commercial form and constitution:

SO3NB SOQNB.

2 z 2 S0s 8 OCu-0 NH-CO-CHa l 5 1 l (mac-04m 0 on o 1 g. NamS-O-CHTCHZ-SOQ-Nm- 0 NH The bath furthermore contained, per liter of water: I 1 cc. ofsodium hydroxide solution 38 Be,

3 of sodium carbonate, and soaNa 50 g. ofsodium sulfate.

Then, 10 cc. of 60 percent acetic acid were added per liter of dyebath, the dyebath was heated to 125 C. and kept for g l one hour at this temperature. The goods were then rinsed and soaped, rinsed again and dried.

A bicolored dyeing was thus obtained. in which the polyester portion of the fabric had an orange shade and the cellulose fiber portion a blue shade.

We claim:

1. A process for exhaust dyeing of a fibrous material composed of a mixture of cellulose fibers and linear polyester fibers in a single aqueous dyebath containing a reactive dyestuff and a disperse dyestuff which comprises treating said fibrous material at a temperature of about 20 C. to about 80 C. in an aqueous dyesbath that contains said reactive dyestuff. said disperse dyestuff and an alkaline agent to adjust the pH of said dyebath to between about 9 and about 12 until said cellulose fibers are dyed with said reactive dyestuff. adding a free The bath additionally contained, per liter of water:

1 cc. of sodium hydroxide solution of 38 Be 3 g. of sodium carbonate and 40 50 g. of sodium sulfate.

Then, 10 cc. of 60 percent acetic acid were added per liter of dyebath, the dyebath was heated to 125 C. and kept for one hour at this temperature. The goods were then rinsed and soaped as usual, rinsed again and dried. g

A navy blue dyeing was obtained in which the polyester and staple fiber portions of the mixed yarn were well dyed tone-ininorganic acid or a free organic acid to said dyebath to adjust AM 2 said pH to between about 3.5 and about 6, and completing the dyeing of a temperature of about 95 C. to about 140 C. until Dyeing was effected a manner analogous to that said polyester fibers are dyed with said disperse dyestuff. described in example 1 using the same textile material but the 2 A process according to claim 6 wherein Said cellulose followmg dyestuffs: fibers are dyed at a temperature of about 40 C. to about 60 CN C. l Hzz- Ha 3. A process according to claim 1 wherein said polyester 0.13 g. O;NN= -N fibers are dyed at a pH of about 4.5 to 5.5.

4. A rocess accordin to claim 1 wherein said olyester CHrCHrO CO CH3 fibers ar dyed at a tempe rature of about 95 C. to aiFout 1 10 0.18 g. HaC-CO-NH 0H OCH; C. and said dyebath contains a carrier for said disperse I I l dyestufffor dyeing said polyester fibers.

-N=N 5. A process according to claim 1 wherein said reactive dyestuff contains as a reactive moiety a vinylsulfone group or NaOaS SOaNa S orCHz-CHz-O-S OaNa a group that forms a vinylsulfone group in an alkaline medium. 

